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IS 2441 (1984) : Code of practice for fixing ceiling
covering [CED 13: Building Construction Practices including
Painting, Varnishing and Allied Finishing]
Jawaharlal Nehru
'Step Out From the Old to the New"
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Satyanarayan Gangaram Pitroda
Invent a New India Using Knowledge
Bhartrhari — Nitisatakam
''Knowledge is such a treasure which cannot be stolen"
^'^^^r
k
BLANK PAGE
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PROTECTED BY COPYRIGHT
Indian Standard
IS : 2441 - 1984
( Reaffirmed 2000 )
CODE OF PRACTICE FOR
FIXING CEILING COVERINGS
{First Revision)
UDC 69-025-4 ; 69-024^ 15 : 006'76
©Ccp^fight 1985
INDIAN STANDARDS INSTIT,UTION
MANAK BHAVAN, 9 BAHADtJR SHAH ZAFAR MARG
NEW DELHI nCMXS
Gr7 March 1985
IS t 2441 - 1984
Indian Standard
CODE OF PRACTICE FOR
FIXING CEILING COVERINGS
( First Revision )
Building Construction Practices Sectional Committee, BDC 13
Chairman
Shri G. p. Malik
C-4/38, Safdarjung Development Area,
NewDelhi-110016
Members Representing
Sksi p. D. A»gasv/ai. Public Works Department, Government of
Uttar Pradesh, Lucknow
Shri R. K. Mathub ( Alternate )
Shki D, P*. Batlivala Ehabha Atomic P^esearch Centre, Bombay
Shri B. K. Chakbaborty Housing and Urban Development Corporation Ltd,
New Delhi
Shbi S» M, Goei. ( Alternate }
Chief En'gineer ( Bldgs ) Public Works Department, Government of
Tamil Nadu, Madras
Superintending Ekgineeb
( Special Building Circle ) ( Alternate )
Chief Engineer- cum- Addl Public Works Department, Government of Rajasthan,
Secretary ( BR ) Jaipur
Executive Engineer ( Alternate )
Chief Engineer ( Training ) Central Public Works Department, New Delhi
Superintending Engineeb
( Training ) ( Alternate )
Shri K. DevabajaN Engineer-in-Chief 's Branch, Army Headquarters,
New Delhi
Shbi A, V. Gopalkbishna ( Alternate )
DiBECTOR, Architecture Research, Designs and Standards Organization
( Ministry of Railways ), Lucknow
Joint Director, Architec-
ture ( Alternate )
Shri S, S. Gill Public Works Department, Government of Punjab,
Chandigarh
Shbi M. Kabtikayan Builders' Association of India, Bombay
Shbi R. L. Kumab Institution of Surveyors, New Delhi
Shbi V. G, Patwabdhan ( Alternate)
( Continued on page 2 )
© Copyright 1985
INDIAN STANDARDS INSTITUTION
This publication is protected under the Indian Copyright Act ( XIV of 1957 ) and
reproduction in whole or in part by any means except with written permission of the
publisher shall be deemed to be an infringement of copyright under the said Act.
IS : 2441 - 1984
( Continued from page 1 )
Members Representing
Shri M. Z. Kurien Tata Consulting Engineers, Bombay
Shri G. K. Majumdar Hindustan Prefab Ltd, New Delhi
Shri H. S. Pasricha ( Alternate )
Shri R. C. Mangal Central Building Research Institute ( CSIR ),
Roorkee
Shri J. S. Sharma ( Alternate )
Shri B. V. B. I*ai Concrete Association of India, Bombay
Shri P. Srinivasan ( Alternate )
Shri P. K. Pandare: State Bank of India, Bombay
Shri K. S. Pruthi Forest Research Institute and College, Dehra Dun
Shri S. G. Ranadive Indian Institute of Architects, Bombay
Shri Rummy Shroff ( Alternate )
Representative Bureau of Public Enterprises, Ministy of Finance
Representative Central Road Research Institute, New Delhi
Representative Life Insurance Corporation of India, Bombay
Deputy Chief Engineer
( North ) ( Alternate )
Shri K. S. Srinivasan National Buildings Organization, New Delhi
Deputy Director ( Alternate )
Shri Sushil Kumar National Buildings Construction Corporation Ltd,
New Delhi
Shri S. R. Tambe Public Works & Housing Department, Bombay
Shri B. T. Unwai^la The Institution of Engineers ( India ), Calcutta
Shri G. Venkatesulu Ministry of Shipping & Transport ( Roads Wing ),
New Delhi
Shri M. V. Sastry ( Alternate )
Shri G. Raman, Director General, ISI ( Ex-officio Member )
Director ( Civ Engg )
Secretary
Shri A. K. Saini
Assistant Director ( Giv Engg ), ISI
Covering Veneering and Glazing Subcommittee^ BDC 13 : 10
Convener
Shri J. R. Bhalla Indian Institute of Architects, Bombay
Members
Architect, PWD Public Works & Housing Department, Government
of Maharashtra, Bombay
Shri S. R. Vaidya ( Alternate )
Shri S. K. Chanda Public Works Department, Government of
West Bengal, Calcutta
Chief Architect Central Public Works Department, New Delhi
Sr Architect ( H&TP ) II ( Alternate )
Shbi G. K. Damani Alumilite Pvt Ltd, Calcutta
Shri V. Mishra ( Alternate )
( Continued on page 27 )
IS : 2441 - 1984
Indian Standard
CODE OF PRACTICE FOR
FIXING CEILING COVERINGS
( First Revision )
0. FOREWORD
0.1 This Indian Standard ( Firiit Revision ) was adopted by the Indian
Standards Institution on 31 May 1984, after the draft finalized by
the Building Construction Practices Sectional Committee had been
approved by the Building Division Council.
0,2 Coverings are fixed on to the ceiling to give a decorative appearance,
to conceal projections, such as beams occurring underneath the floor slab,
to provide a false ceiling, and sometimes to obtain special acoustic effects
and insulation against heat and cold. The ceiling being a prominently
exposed building feature, even a slight fault in the joints or in the align-
ment of the ceiling coverings will be perceptible and lead to unsightly
appearance; therefore, care is called for in the installation of the support-
ing frame and fixing of coverings. This standard is intended to provide
guidance with regard to the various aspects of the w^ork of fixing ceiling
coverings.
0.2,1 This standard was first published in 1963. This is being revised
to incoi-porate the modifications found necessary as a result of experience
gained during the use of this standard. In this revision fixing details
for additional types of ceihng coverings have been included and details
for existing types modified.
0.3 This standard is intended chiefly to cover the technical provisions
relating to fixing ceiling coverings; it does not cover all the necessary
provisions of a contract.
0.4 For the purpose of deciding whether a particular requirement of this
standard is complied with, the final value, observed or calculated,
expressing the result of a test or analysis, shall be rounded off in accord-
ance with IS : 2-1960*. The number of significant places retained in the
rounded off value should be the same as that of the specified value in this
standard.
•Rules for rounding off numerical values ( revised ).
3
IS : 2441 - 1984
1. SCOPE
1.1 This code covers the details of fixing the following types of ceiling
coverings;
a) Insulating building board ceiling,
b) Hardboard ceiling,
c) Plaster of paris ceiling,
d) Plaster of paris tiles,
e) Gypsum plaster board ceiling,
f ) Plywood and blockboard ceiling,
g) Asbestos cement building board ceiling,
h) Wooden cover fillets beading for ceiling,
j) Cloth ceiling,
k) Aluminium sheet ceiling,
m) Expanded polystyrene ceiling, and
n) Mineral wool board ceiling.
Note — The fabrication and fixing of timber ceilings are covered in IS : 5390-
1984*.
2. TERMINOLOGY
2.1 Framework — Wooden or metal framework consists of longitudinal
bearers and cross bearers by means of which the ceiling boards or cover-
ings are supported ( see Fig. 1 ).
3. NECESSARY INFORMATION
3,1 For efficient planning and execution of the work, detailed data and
information with regard to the following shall be furnished:
a) The situation and purpose of providing the ceilings and any
special requirements for the ceiling along with detailed drawings
of the building;
b) Area of ceiling to be covered;
c) Location of lights, fans and apertures for air-conditioning and
ventilation, location of skylights, rooflights, etc, in the case of
ceilings to sloped or pitched roofs;
d) Type of framework for supporting the ceiling covering;
e) Type and size of ceiling boards to be used for covering;
♦Code of practice for construction of timber ceiling {first revision ).
IS 1 2441 - 1984
■ Rcc sl^o
LONGiTUDlNAL AND CROSS
BEARERS 60 mm DEEP
ArJD 4 0 mrn WIDE
MS FLAT
SLOTF.D .y>'
HOLE--"'-
A PREPERABLF
ALTERI^ATIVE
TO DETAIL A
/ .^^ ^' Y / /// AY/ \ //
/c:£rE^r-^~'"'^"'r£^ laiogle iron cleats
CROSS JUNCTION
/ — -w^-y^- -1^
,<L. ^ RJ^ <:^/--^-:.:z::^4^^^
Fig. 1 Details of Ceiling Frame Suspep^ded from RCC Slab
f ) Matching treatment at the junction of the ceiling with the wall
or wall covering and at corners of ceiling and wall, matching
treatment at the points of fixing of ceiling lights, fans, etc;
g) Type of finishing treatm.ent to be applied on the ceiling covering,
if any; and
h) Type of joints in the ceiling covering and type of beading, if any,
to Idc used.
3.2 All information as in 3.1 shall be made available to those who are
responsible for fixing the ceiling coverings. Necessary drawings and
instructions for preparatory work shall be made available.
3.3 The work shall be properly planned and co-ordinated with those
who are responsible for electrification, air-conditioning, fitting and fixing
of telephone lines, etc. The entire ceiling covering work shall be
IS : 2441 - 1984
executed simultaneously in proper sequence and in order to avoid any
dismantling subsequently after fixing of ceiling covering and finishing.
3,4 The sequence of work shall be planned and properly organized, so
that after commencement the ceiling work progresses in a smooth manner
without any hindrance, delay or bottleneck at any stage till finishing is
given.
4, DESIGN CONSIDERATIONS
4.1 General — The function of ceiling may be manifold, as for example
concealing roof framework, beams, air-conditioning ducts, and electrical
wiring, providing sound insulation and aesthetic requirements. For design
of the ceiling the following considerations shall be generally necessary:
a) Strength, stiffness and dimensional stability, choice of nails and
screws, battening, beading, method of fixing, etc;
b) Durability and vermin protection ( see IS ; 401-1982* );
c) Moisture resistance;
d) Acoustic properties ( see IS : 1950-19621 );
e) Heat insulation ( for thermal insulation properties of different
types of boards for ceiling coverings, reference may be made to
IS : 1414-1962J );
f ) Fire protection ( see IS : 1642-1 960§ );
g) Vapour permeability; and
h) Illumination considerations,
4.1.1 The fixing of the ceiling coverings shall reasonably permit
adjustment*? for thermal expansion and moisture movemerits of the
coverings. The coverings shall be free from cracks, bending or distortion.
From practical considerations it is advisable to provide easily removable
ceiling covering at suitable locations for periodical inspection to assess the
condition of wooden frames, strap hangers, screws, etc.
4.1.2 When using special types of sound insulation boards, the
manufacturer's instructions regarding selection and fixing shall be
followed.
4.1.3 The screws and nails shall be rustless. These shall conform to
relevant Indian Standards and in addition shall be coated wherever
specified in relevant clauses.
•Code of practice for preservation of timber ( tkir/f revision ).
tCode of practice for sound insulation of non-industrial buildings.
JGode of practice for fixing wall coverings.
§Code of practice for fire safety of buildings (general); Materials and details of
construction.
IS : 2441 - 1984
4.2 Frame Strength and Stability
4.2.1 The frame to support the ceiling shall be designed for structural
strength and stability taking into consideration the spacing of truss
members and the sizes, weight and strength of ceiling coverings to be
fixed. Structural design of timber members of frame shall be in accord-
ance with IS : 883-1970*.
4.2.2 Generally false ceiling to RCG slabs may be provided to cover
projecting beams, frames and slabs at different levels, and also service
lines and installations.
Note — In public halls where RCC slabs are not provided in one level, use of
false ceiling shall achieve better finish, acoustic and thermal insulation, concealed
lighting, etc.
4.2.3 The suspenders used for supporting framework for false ceiling
to RCG slabs shall be of length sufficient to reach the ceiling frame; it
shall be anchored adequately to structural concrete abo%'e so as to obtain
the required support for the ceiling ( see Fig. 2 ).
4.2.4 Where the members of ceiling framework span more than
900 mm centre-to-centre additional cross battens shall be provided to
stiffen them,
4.2.5 Geiling boards whose mass is not more than 5 kg/m^, may be
fixed directly to RGG slabs by means of fixing plugs, bolts or other
suitable devices.
4.2.6 Where double ceiling boards are provided, such as in air-condi-
tioning installations and in cold storage rooms, the first layer of ceiling
board may be fixed to the ceiling with plugs or other fixing devices
( see IS : I946-1961| ) in the concrete slabs at required spacings,
4.3 Mass — For different types of ceiling the mass shall be as given in
IS : 1911-1967J.
5* FIXING OF COVERINGS
5.1 Insulating Building Board
5.1.1 Materials
5.1.1.1 Timber — Timber for making ceiling framework and beading
shall be from any of the species of timber given in IS : 3629-1966§,
♦Code of practice for design of structural timber in buildings ( third revision ).
fCode of practice for use of fixing devices in walls, ceilings and floors of solid
construction.
JSchedule of unit weights of building materials (first revision ).
§Specification for structural timber in buildings.
STRAP
HANGER
ROD HANGER
CLIPS FOR CONNECTING
TWO MEMBERS IN
LONGITUDINAL ALIGNMENT
2A STRAP HANGER WITH
ANGLE RUKNER
ROD HANGER
2B ROD HANGER WITH
PIPS RUNNER
tfi
1^
00
ANGLE
RUNNERS-
2F ANGLE AND TEE CESLING-
MEMBER SUSPENDED
FROM ROD HANGER
20 STRAP HANGER WITH VERTI-
CAL-SLIDING ARRANGEMENT
VARIOUS TYPES
OF CLIPPING /
DEVICES -x^^
2G HORlZONT>.L-SL!0:f^G HAMGErj WITH
DOUBLE ANGLE TRUSS MEN^.BER
2E Fixing of ceiling board with
STUD clamp
CEILING BOARD
CLiF FOR FIXING BOARDS
ON BOTH SIDES
2H SUSPENSION OF CEiUNG BO^kH
VrVTH \;ARiOUS TYPES OF CLi^S
Different methods of attachment of hangers to Top Members are illustrated in 2A, 2B, 2D and 2G, and to Ceiling
Frames are illustrated in 2A, 2C; 2D, 2F and 2G,
Use of clips, studs and hooks for fixing boards are illustrated in 2H and 2E.
Fig. 2 Details Showing Some Typical Methods of Suspension of Ceiling Frame fROm
Structural Members
IS: 2441 -1984
5.1.1.2 Insulating building boards — This may be particle boards
conforming to IS : 3129-1965* or fibre insulating boards conforming to
IS : 3348-19651.
5.1.1.3 Nails — Nails shall conform to IS : 723-1972+. The length
of nails shall generally be equal to the thickness of the board plus 25 mm
so that their grip on the frame scantling will not be less than 25 mm.
Galvanized lost head nails of diameter 2'80 mm conforming to
IS : 6738-1972§ may be used when joints are left exposed. Where joints
are to be covered with beading, galvanized felt nails of 2'50 mm diameter
conforming to IS : 6730-197211 may be used.
5.1.1.4 Screws — If screws are used, they shall conform to IS : 6760-
19721f wood screws.
5.1.2 Handling
5.1.2.1 Boards shall be carefully handled, stored and conditioned
before use. The following precautions shall be taken:
a) When transporting or stacking at site, the boards should be laid
flat on an even foundation of battens and covered with tarpaulins
to prevent damage by changing weather conditions, soiling by
earth, mortar, concrete or other rubbish and damage to edges
and cracking.
b) When handling boards shall be carried on edge and not flat, to
prevent buckling and cracking.
c) Before use, the boards shall be conditioned to the humidity of the
atmosphere by stacking them loosely on edge for a period of 24
to 48 h so that air can have free access to both sides of each sheet
during that period.
5.1.3 Fixing
5.1.3.1 Cutting boards to required size — The boards shall be cut to the
required size to conform to the pattern of panelling as shown in the
detailed drawings and each panel shall be in one whole piece. The
cutting shall be done with a carpenter's panel saw with fine teeth. The
boards should be sawn with the face side up. By placing a strip of
waste under the sheet and sawing through both the layers simultaneously
a fine and even edge can be obtained. Unless specially mentioned joints
♦Specification for particle board for insulation purposes.
fSpecification for fibre insulating boards.
tSpecification for steel countersunk head wire nails {first revision ).
§Specification for panel pins and lost head nails.
^Specification for felt nails.
^Specification for slotted countersunk wood screws.
IS : 2441 - 1984
in the boards shall be with square or slightly bullnosed edges. The edge
shall then be lightly sandpapered to make them smooth.
5*1*3.2 Timber frame — Timber frame shall be fixed by the method
described in 5*2.3. Aluminium frame may also be used in place of
timber frame work,
5.1*3.3 Fixing of insulating building boards ceiling framework — Building
boards shall be fixed with lengths parallel to all joints centred over the
the framing members. Where joints are to be covered, the boards shall
be spaced 3 to 6 mm apart. Where joints are to be left exposed the
sheets shall be butt laid with their edges abutting in moderate contact,
but without having to force them into place The boards shall be
supported and held tight to the grounds with timber pieces the latter
being moved outwards as the nailing proceeds. The boards are first
nailed to intermediate framing member proceeding from the centre of
the board outwards, the edges being nailed last.
5*1*3.4 Where joints are to be left exposed, the outer rows of nails
shall be placed at 100 mm centres and about 12 mm from edge of the
sheet- The rows in the middle of the sheet shall be placed 200 mm
apart. Nails in the outer rows on either side of joint shall be paired and
not staggered. Nails shall be countersunk in the underside of the board
with a suitable punch. Care shall be taken in driving the nails so that
the sheets are not marked by hammer blows.
5*1.3.5 Where joints are to be covered with beadings, felt nails
shall be used instead of lost head nails. The spacing of the nails in the
interior rows in boards shall be the same as in 5.1.3.4. In the outer rows
at edges to be covered by beadings, the nails shall be spaced at 200 mm
centres in each row but with the nails staggered. The beadings shall
then be fixed over the sheets with screws at 200 mm centres in each row
with screws in two rows staggered and passing through beading, sheet
and framming, so that ultimately the facing of the fixing ( nails and
screws taken together ) in each row shall be 100 mm centres so far as the
sheets and frames are concerned.
5*1.4 Finishing
5.1*4.1 The exposed side of the board shall be truly level, and plane
without any local bulges or sags. The joints shall be truly parallel
and/or perpendicular to the walls. The width of joints shall be uniform.
Care shall be taken to see that the uniformity of the colour of the boards
is not spoilt during the fixing operations.
Where the joints are required to be covered, beading shall be fixed
as in 5.8, The ceiling shall be treated as required with suitable finishing
materials.
10
IS : 2441 - 1984
5.2 Hard Board
5.2.1 Materials
5.2.1.1 Timber — The timber for making ceiling framework and
beading shall be from any of the species of timber given in IS : 5390-
1984*.
5.2.1.2 Hard Board — Medium type hard board conforming to
IS : 1658-19661 shall be used for ceiling purposes.
5.2.1.3 Xails — The nails shall conform to IS : 723-1972J.
5.2.1.4 Screws — The screws shall conform to IS : 6760-1972§.
5.2.2 Handling
5.2.2.1 Hard board shall be handled in the same manner as for the
insulating building boards described in 5.1.2. The conditioning of the
hard board sheets before use shall be done in the manner described
in 5.2.2.2.
5.2.2.2 The sheets shall be damped with water on the textured face
before they are fixed. This shall be done by brushing the textured face
evenly and carefully with a sponge or swab soaked in water. After this
the sheets shall be stacked with the damped sides against each other in
pairs and left to remain for a period of 24 to 48 hours. During this
conditioning, the sheets should be sheltered from sun and strong heat.
5.2.3 Fixing
5.2.3.1 Framework — The longitudinal battens and cross battens
supporting the ceiling shall be spaced according to the size of the boards
to be fixed.
5.2.3.2 The size of battens may range from 60 to 75 mm X 50 mm
and the spacing may range from 450 to 600 mm for longitudinal battens
and 600 to 1 200 mm for cross-battens depending on the size of the
boards. The battens shall be treated with two coats of preservative
paint preferably odourless before the ceiling is fixed. The preservative
shall be allowed to dry up before fixing sheets.
Note — Treatment with two coats of preservatives is a temporary measure
reference shall be made to IS : 401-1982JI for details.
*Gode of practice for construction of timber ceilings (Jirst revision ).
fSpecification for fibre hard board ( revised ).
tSpecification for steel countersunk head wire nails {first revision ).
§Specification for slotted countersunk head screws.
[(Code of practice for preservation of timber ( second revision ).
11
IS : 2441 - 1984
5.2.3.3 All edges of the hard board shall be fixed to the frame
battens by means of screws. Along the edge line of the board the screws
shall be at a spacing of 75 mm centre to centre and shall have a clear-
ance of at least 10 mm from the edge line. Along the lines of intermediate
supports, the screws may be spaced at 150 to 200 mm centre to centre.
All the screws shall be countersunk.
5.2.3.4 Screws shall be rustless. The steel screws if used, shall be
coated with either brass, nickel or cadmium. The length of the screws
shall be 25 mm for 3 to 6 mm thick board and 30 or 35 mm for 8 to
12 mm thick board.
5.2.3.5 The cutting and chamfering of the sheets shall be done in
the same manner as for insulating building boards described in 5.1.3.
5*2.3*6 Jointing — Joints shall not be normally filled with plaster,
but where the hard boards are to be cement plastered the joints shall be
left with gap of about 6 mm which shall be covered with scrim and
bedded in cement plaster before the finishing coat of plaster is applied.
5.2.3.7 If the hard board specially moulded on the edges are used,
the manufacturer's instructions for cutting at site shall be followed.
5.2.3.8 In the case of rebated edges, screwing shall not be done
through the rebates.
5.2.3.9 Open joints may be covered with strips of various materials
such as the following;
a) Wooden beading as described in 5*8;
b) Plain strips out from sheets of the same material as the boards or
mouldings of hard boards separately procured for use as cover
strips, or special types of moulded cover strips supplied by the
manufacturer;
c) Metal cover strips such as aluminium or chromium plated
metal;
d) Shaped plastic strip; and
e) Linen backed adhesive strip.
Cover strips shall be screwed along the centre line of the joints, so
that the fixing of screws pass through the open joints. The spacing of
screws shall be at least 150 to 200 mm centre to centre. Special type
of cover strip of hard board, metal, plastic, etc, may be fixed in accor-
dance with the manufacturer's instructions.
Linen-backed adhesive may be fixed by wetting the linen and
pressing over the edges of the boards.
5-2.4 Finishing — Details of work shall be same as given in 5.1.4.
12
IS : 2441 - 19B4
5«3 Plafttet* of Paris
5.3.1 Material
5.3.1.1 Timber — Timber for making ceiling framework, wooden
strips of laths shall be from any of the species of timber given in
18:5390-1984*.
5.3.1.2 Plaster ofparis — Plaster of paris shall conform to IS : 2547-
19761.
5.3.2 Fixing
5.3.2.1 Frame — In case of sloping roofs, wooden battens of suitable
section ( at least 50 mm X 60 mm ) shall be firmly fixed as main supports,
to the underside of the beams of the trusses at required centres by means
of bolts and nuts of proper size.
In case of flat roofs, battens shall be securely fixed to the walls and
pillars by holding down bolts and shall be fastened to the slabs above
with iron straps or mild steel bars of suitable sections anchored therein.
Gross battens of 50 mm X 40 mm section at about 400 mm centres shall
then be fixed at right angles to the main battens. The framework shall be
treated with suitable wood preservatives before it is covered with ceiling.
The underside of the framework shall be true to planes and slopes.
Aluminium frame may also be used if specified in the item of work.
5.3.2.2 Wooden strips or laths — Wooden strips or laths 25 mm X 6 mm
of first class kail wood (unless otherwise stipulated specifically in the
description of the item ), shall be fixed to the cross battens, in parallel
rows with gaps of 10 mm in between adjacent rows, by means of felt
nails as per IS : 6730-i972t. The strips shall be fixed butt jointed and
not overlapped. The joints shall be staggered. The minimum length
of strips to be used shall be 1 '5 m depending upon the length of strips
required.
5.3.2.3 Rabbit wire mesh — The mesh shall be fixed with nails at
pitch of 150 to 200 mm to the underside of wooden strips at their
junction with the battens. The wire mesh shall be straight, tight and
perfectly true to planes and slopes and without any sagging, and shall
be slightly below the underside of the laths to allow the plaster to encase
the mesh alround.
5.3.2.4 Application of plaster ofparis — The plaster of paris shall be
mixed with water to a workable consistency. The plaster of paris shall
be applied to the underside of the laths over the rabbit wire mesh in
*Uode of practice for construction of timber ceilings [Jirst revision ).
fSpecification for gypsum building plaster.
^Specification for felt nails.
13
IS : 2441 - 1984
suitable sized panels and finished to a smooth surface by steel trowels.
The plaster shall be applied in such a manner that it fully fills the gaps
between the laths. The thickness over the laths is as specified in the
description of the item. Joints shall be finished flush to make ceiling
in one piece. Finished surface shall be smooth and true to plane, slopes
or curves as required.
5.3.2.5 Thickness — The thickness of the plaster of paris ceiling shall
not be less than 12 mm.
5.4 Plaster of Paris Tiles
5.4.1 Materials
5.4.1.1 Timber — Timber for making ceiling framework, shall be
from any of the species o£ timber given in IS : 5390-1984*.
5.4.1.2 Plaster of paris — This shall conform to IS : 2547-19761.
The thickness of the plaster of paris tiles shall not be less than 12 mm.
5.4.1.3 Hessian cloth — This shall conform to IS : 2818 ( Part 1 )-
1971J. The hessian cloth shall be of an open webbed texture.
5.4.2 Preparation
5.4.2.1 Tiles of plaster of paris reinforced with hessian cloth shall
be prepared to the required size. The maximum sizes of tiles shall be
limited to 750 mm in each direction and thickness shall be 12 mm.
Wooden forms of height equal to the thickness of tiles ( 12 mm ) shall
be placed on a truly level and smooth surface such as a glass sheet.
The section of form sides shall be such that the edges of the tiles
shall be provided with a neatly formed chamfer alround of 5 mm width
and 8 mm depth, unless the tiles are to be provided with cover fillets
over joints in which case the edges of the tiles shall be truly square. The
glass sheet or surface on which the form is kept and the forms sides shall
be given a thin coat of non-staining oil to facilitate easy removal of the tile.
Plaster of paris shall be evenly spread into the form up to about half of
the depth and hessian cloth shall be pressed over the plater of paris
layer. The ends of the hessian shall be turned over at all edges to form
a double layer to a width of 50 mm. The plaster below and above the
hessian cloth shall intermix with each other and form an integral mass.
The form shall then be filled with plaster of paris which shall be
uniformly pressed and then wired out to an even and smooth surface.
Tiles so moulded shall be allowed to set initially for an hour and then
removed from the form and allowed to dry and harden for about a
*Code of practice for construction of timber ceilings {first revision ).
tSpecification for gypsum building plaster.
+ Specification for Indian hessian: Part 1 General {first rebision ).
14
IS : 2441 - 1984
week. A good tile after drying and hardening shall give a ringing
sound when struck. The tiles shall be true and exact to shape and size
and with clean and regular chamfers. The exposed faces shall be truly
plane and smooth.
5.4*3 Fixing
5«4.3«1 Frame — The timber frame shall be provided as described
in 5*2.3. The width of the scantlings shall be sufficient to provide a
minimum nailing surface of 60 mm. The longitudinal and header
scantlings shall be so arranged that the tiles can be fixed to form the
desired panel arrangement and there is supporting scantling under each
and every edge of the tiles. Aluminium frame may also be used in this
type of ceilings.
5*4.3.2 Fixing — The tiles shall be fixed to the cross battens of the
ceiling frame with 40 mm long brass screws as in IS : 6760-1972* at
spacings not exceeding 200 mm centre to centre on all edges. The tiles
shall be laid with their edges in just close position to the adjoining
tiles without any gap in between. The line of screws shall be not less
than 15 mm away from the edge of the tiles. The screws shall be slightly
countersunk in holes of tiles. Holes for screws shall be drilled. The
countersunk heads of screws shall be covered with plaster of paris and
smoothly finished.
Where a surface unbroken by visible joints is required, the joints
shall be filled with plaster of paris and trowelled smooth so that the
whole surface appears as one without any joints.
5*5 Gypsum Plaster Board
5.5.1 Materials
5*5.1*1 Gypsum plaster boards — Gypsum plaster boards shall conform
to IS : 2095-19641.
5.5.1.2 Mils — Nails shall conform to IS : 723-1972$. The nails
used for taking gypsum boards shall be 2'00 mm size. The length of
nails shall be as follows:
a) for 10 mm thick boards 30 mm
b) for 12*5 and 16 mm thick boards 40 mm
5.5.1.3 Screws — Screws used for fixing gypsum boards shall
conform to IS : 6760-1972§, Steel screws without brass or nickel
coating shall not be used.
♦Specification for slotted countersunk head wood screws,
fSpecification for gypsum plaster boards,
^Specification for steel countersunk head wire nails {first revision ).
§Specification for slotted countersunk head wood screws.
15
IS : 2441 - 19«4
The si2e of the screws shall be 3'10 or 3*45 mm diameter and the
length as follows:
a) for 10 mm thick boards 30 mm
b) for 12'5 and 16 mm thick boards 35 or 40 mm
5.5.2 Fixing
5.5.2*1 Fixing of gypsum plaster boards to framework — The gypsum
plaster boards shall be fixed as given in 5.2.3.
5.5.2.2 Jointing — The boards shall be fixed with a joint with
clearance of abouts 6 mm. The joints shall always be in perfect line and
plane. Jointing may also be provided in a decorative pattern.
5.5.2.3 Finishing of joints — The joints shall be filled with gypsum
plaster or other finishing materials recommended by the manufacturers
of the board. After filling the joints, a thick skin of the finishing
material shall be spread about 50 mm wide on either side of the joint
and shall be trowelled dry with a reinforcing scrim cloth about, 100 mm
wide. When itietal scrim is used, a stiffer plaster may be necessary to
enable the trowelling of the scrim down to the board. The joints may
also be left open if desired ( see Fig. 3 ),
REINFORCED SCRIM
CLOTH
GYPSUM PLASTER OR
FILLING MATERIAL
WOODEN STRUCTURAL
BEAM
OPEN JOINTS-^ '^^ '^'^''fl.l^Jn.l^'"'"
FROM EDGE
Fig. 3 Finishing Treatment for Joints in Gypsum Board Ceiling
16
IS : 2441 - 2984
5.6 Plywood and Blockboard
5.6.1 Materials
5.6.1.1 Timber — Timber for making ceiling framework shall be
from any of the species of timber given in IS : 5390-1984*.
5.6.1.2 Plywood — Plywood shall conform to IS : 303-1975t.
5.6.1.3 Blockboard — Blockboard shall conform to IS : 1659-1969J.
5.6.1.4 Screws — The screws shall conform to IS : 6760-1972§.
5.6.2 Fixing
5.6.2.1 Framework — Longitudinal battens and cross battens
supporting the ceiling shall be spaced in section as detailed, taking into
consideration the size and shape of the board, thickness of the board,
including its strength and weight, the pattern of the figure and grain
matching in the case of decorative boards. The sizes of battens may
range from 60 to 75 mm X 40 to 50 mm.
5.6.2.2 For boards in thickness 4 mm to 10 mm, spacings vary from
450 to 600 mm for longitudinal battens and 600 to 1 200 mm for cross
battens. For boards above 10 mm thickness, the above spacings may
vary from 600 to 900 mm for longitudinal battens from 900 to I 300 mm
for cross battens.
5.6.2.3 After fixing, the framework shall be checked with regard to
the level position of its outside and for proper fixture and joints,
5.6.2.4 Fixing
5.6.2.5 The plywood or blockboard shall be checked for correct size,
squareness of adjacent sides and laying patterns. In the case of decora-
tive boards, the patterns and figure matching should be as per details
and put on paper at site and the boards preferably numbered for -their
positions. Any board so required shall be cut to the required plan.
5.6.2.6 Where necessary, particularly, when it is not sufficient thick
to be self-supporting from edge to edge, plywood may be stiffened along
the edges and also in intermediate positions by stiles or narrow strips of
v^^ood, metal, plastic or other materials.
*Code of practice for construction of timber ceilings (first^ revision ).
tSpecification for plywood for general purposes ( second revision ).
^Specification for blockboards [first revision ).
§Specification for slotted countersunk head wood screws.
17
IS : 2441 - 1984
5*6.2*7 The boards shall be carefully lifted in a predetermined
manner and fixed on to the frame by use of wood screws. All the edges
shall be fixed to the frame members by screws spaced 75 mm centre to
centre for 4 to 6 mm thick plywood; for thicker boards the centre ta
centre spacing of these screws may be at about 15 times the thickness.
The screws shall have a clearance of 10 mm from the edge line. At the
lines of intermediate support, the screws shall be fixed at centre to centre
spacing not exceeding 25 times the thickness. All the screws shall be
countersunk.
5«6.2«8 The screws shall be rustless. The screws shall be fixed
starting from one corner and extending to both sides to fix the board
flat and level. The length of the screws shall be as follows:
a) for boards up to 7 mm 25 mm
b) for boards above 7 mm up to 12 mm 35 mm
c) for boards above 12 mm Thickness +20 mm
5«6,2.9 Jointing
5.6.2.10 The boards may be butt jointed with a minimum clearance
of 2 mm.
5«6.2«I1 The joints, if left open, shall be filled with painter's putty
and brought to level or may be cut to ' V ' shape. These may also be
left open levelled or parallel grooved using plane and a chisel or grooving
cutter. The boards may also be pre-cut and edges rounded before
fixing. In the case of decorative boards, the joints may be coloured to
match the general colour and pattern of the ceiling boards,
5.6.2.12 The joints may also be rebate-jointed or jointed with tongue
and groove. Screws shall in that case not be fixed through the rebate.
5.6.2.13 Alternatively, the open joints may be covered by a
moulding or strips.
5.6.2.14 When fixing moulding in case of decorative boardsj care
shall be taken that their colour, shape and size are selected appropriate
to the decorative pattern of the ceiling.
5.6.3 Finish
5.6.3.1 The ceiling after fixing shall be finished by hand-sanding,
where necessary, and given finishes of waxing, polishing, clear varnishing
or painting as required. Finishing of wooden surfaces shall be done in
accordance with IS : 2338 ( Part 1 )-1967*.
♦Code of practice for finishing of wood and wood based material: Part 1 Operations
and workmanship,
18
IS : 2441 - 1984
5*7 Asbestos Gement Building Board
5.7.1 Materials
5.7.1.1 Timber — Timber for making ceiling framework shall be
from any of the species of timber given in IS : 5390-1984*.
5.7.1.2 Asbestos cement building board — This shall conform to IS :
2098-1964t.
5.7.1.3 Screws — The screws shall conform to IS : 6760-19721.
5.7.2 Fixing
5.7.2.1 Framework — This shall be as per details given in 5.2.3.
5.7.2.2 Fixing — The asbestos cement building boards shall be laid
truly parallel or perpendicular to the walls and shall be fixed to the
battens with screws. In fixing the A.C. boards care shall be taken to
avoid rigid fixing as this may cause cracking if the supporting structure
expands or shrinks. The boards shall be fixed with screws to the wooden
frame by means of metal channels and clips as shown in Fig, 4. Holes
in the boards shall be drilled as on no account be punched. No hole
shall be nearer than 12 mm to the edge of the sheet. The board shall
be butt jointed with screws at 150 mm intervals at edges and 300 mm
intervals in the middle. Screws shall be countersunk and covered by
plaster of paris. A gap of 3 to 6 mm shall be kept between the
adjoining edges of the sheets. The joints where required may be
covered with wooden beading as decribed in 5.8.1.3 or with plain strips
out from the sheets of the same material.
WOODEN OR METAL
STRIP AT EACH
SHEET JOINT
Note — For fixing with metal section and clips, reference may be made
to Fig. 2G. '
Fig. 4 Fixing Asbestos Cement Ceiling Boards to Wooden Members
♦Code of practice for construction of timber ceilings {Jirst revision ).
fSpecification for asbestos cement building boards.
^Specification for slotted countersunk head wood screws.
19
IS: 2441 -1984
5,1*3 Finish
5*7.3.1 The ceiling, when completed, shall present a neat and
uniform appearance. Care shall be taken to see that the asbestos cement
boards are not dirted during construction. Usually no finishing treat-
ment of asbestos cement building board ceiling is needed. Ceiling may,,
if required, be painted to the desired shade.
5.8 Wooden Cover Fillets Beading
5,8.1 Materials
5.8.1*1 Timber — Timber used for making beading shall be from
any one of the species listed in IS : 5390-1984*.
5.8.1.2 Screws — These shall conform to IS : 6760-19721.
5.8* 1*3 Beading — The beading shall be planed, smooth over all
exposed faces and true on the rear face. The beading shall be of size
12 mm X 40 mm or of any other size as given in the description of the
item.
5*8*2 Fixing
5.8.2*1 The headings shall be fixed centrally over the butt joints
between the two timber planks or boards with screws in two rows on
either side of the joint. The spacing of the screws in each row shall be
200 mm centres. The screws shall pass through the beading, timber
plank or ceiling board and into the ceiling rafters, with a minimum
grip of 25 mm in the latter and where the beading is to be fixed to the
board above for ornamental purposes there being no framework scantling
above, then the beading shall be fixed with screws which shall be driven
through the full depth of the board and their spacing shall be the same
as before. The screws shall be oiled before insertion and shall be
screwed in by means of a screw driver and in no case the use of a
hammer for fixing the screws is permissible. The screws shall be driven
slightly countersunk below the surface of the beading.
5.8.2*2 The junction of the beading shall be of the fully mitred or
of partly mitred kind as required by the authority. Where joints are to
be fully mitred both the longitudinal as well as cross headings shall be
to the exact length as required by the panel arrangements. Where the
joints are partly mitred variety and the length of the beading in one
direction can run continuously over more than one panel then the
minimum lengths of these headings shall be 1*80 m and the joints shall
come at a corner of the panel and not in the middle of the panel side.
♦Code of practice for construction of timber ceilings (Jirst revision ).
tSpecification for slotted countersunk head wood screws.
20
IS : 2441 - 1984
5.8.3 Finish
5.8.3.1 The beading shall be finished smooth and fixed with such
a workamanship that there is absolutely no gap left between the
beading and the ceiling board or in the joint faces. The beading lines
shall be absolutely straight and parallel. The plane of the underside of
the beading shall be uniform.
5.9 Cloth
5.9.1 Material
5.9.1.1 'Timber — Timber for making ceihng framework and beading
shall be from any of the species given in IS : 5390-1984*.
5.9.1.2 Bamboo — Good quality bamboo shall be used for framework.
The quality of bamboo to be used for the framework shall be approved
before using for the work.
5.9.1.3 Cloth
5.9.1.4 The selection of cloth for the ceiling * depends on the
following factors:
a) External characteristics,
b) Colour,
c) Acoustics properties,
d) Fire resistance and moisture resistance,
e) Method of construction, and
f) Cost.
In general, any type of cloth ( thicker cloth ) can be used as a
ceiling material, depending upon the function and appearance desired in
the room. The cloth for ceiling can be manufactured from either
natural fibres or synthetic fibres. For knowing the exact properties of
the cloth to be used as ceiling material, textile expert shall be consulted.
5.9.1.5 Cloth — Dungry cloth conforming to IS : 749-l978t shall be
used. If canvas or any mill made white drill is used in place of dungry
cloth, it shall be specified. The cloth shall be thoroughly washed before
use to free it from chemicals, otherwise after being whitened it may turn
black.
♦Code of practice for construction of timber ceilings {first revision ).
fSpecification for handloom cotton dungry cloth {first revision ).
21
IS : 2441 - 1984
5.9.1.6 Type of fibres:
a) Natural fibres
1) Cotton
2) Linen
3) Silk and wool
b) Man-made fibres or synthetic fibres
1) Rayon or artificial silk,
2) Glass fibres,
3) Nylon,
4) Decron,
5) Orion or the fibres approved by competent authority.
5»9AJ Scantlings 07 framework — The scantlings for the framework
shall be of 75 mm X 65 mm size, unless otherwise specified. They shall
have a perfectly straight edge and face to which the cloth will be
attached. Other sides may be left rough.
5.9.1.8 Beading — Wooden headings shall be of size 12 mm X 40 mm
or of any other size as given in description of the item and shall be
plained round-edged.
5.9.1.9 Nails — Nails shall conform to IS : 723-1972*.
5.9.1.10 Screws — Screws shall conform to IS : 6760-1972t.
5.9.2 Fixing
5.9.2.1 Framework — The framework of wood bamboo battens shall
be securely spiked to the wall plaster of fixed to wooden blocks let into
the walls and firmly screwed to the underside of the beams or to ceiling
joists where joists are used. The battens shall form square or oblong
panels not more than 1*5 m in length on any side.
5.9.2.2 When the framework is bamboo neat, even width and sand
prepare, split bamboo battens shall be securely nailed to the joists, to
make the same size panels.
5.9.2.3 Fixing — The cloth shall be damped, stretched and nailed to
the upper side of the framework which shall be planned and varnished.
In the case of bamboo framework, cloth shall be tied up to the under-
side neatly by strong string without tearing the cloth.
♦Specification for steel countersunk head wire nails {first revision ).
fSpecification for slotted countersunk head wood screws.
22
IS : 2441 - 1984
5»9,2.4 Beading — To prevent the cloth from blowing and flapping
about, wooden headings, planed and moulded shall be fixed under the
cloth ceiling to form panels. The beadings shall be screwed over the
cloth to the framework above to panels and all round the wall with
screw not further, apart than 150 mm. The wooden beadings shall be
varnished.
5.9«2.5 Finish — The cloth shall be white-washed or distempered.
5.10 Aluminium Sheet
5.10.1 Materials
5.10.1.1 Aluminium trays — The ceiling may be made up of
aluminium ' T ' grid and aluminium trays made of aluminium alloy
sheets of 19 000 or 3 1 000 of IS : 737-1974*. For insulation and acoustic
control, the trays perforated or plain are filled .with either glass wool
or mineral wool blanket of 20 to 40 mm thickness depending on the
job requirement.
5.10.1.2 Grid — The aluminium grid, concealed or exposed shall
be made of specifically extruded aluminium ' T ' section of 63 400 Wp
of IS ; 733-1 975f. The fittings will be made out of aluminium or rust
proofed steel.
5.10.2 Fixing
5.10.2.1 Exposed grid system — In this case, the panels shall be placed
on the aluminium false ceiling grid of inverted ' T '.
5.10.2.2 Concealed grid system — The panels shall be clipped by
means of fine plated spring clips on aluminium ^ T ' grid.
5.10.3 Finish
5.10.3.1 Aluminium false ceiling trays supplied in painted or
anodised or mill finish with ' T ' grid shall match the back ground. .
5.10.3.2 Painted finish — The trays and * T ' are chemically treated
and painted with acrylic resin paint which does not attract fungus and
does not discolour.
5.10.3.3 Natural satin anodised finish — The trays and Ts shall be
chemically cleaned, treated and anodised in controlled conditions to the
required specifications. The specific grade suitable for this purpose is
AG 10 of IS : 1868-1982?. The anodised surface shall finally be sealed
for life-long finish.
♦Specification for wrought aluminiutn and aluminium alloys, plate ( for general
engineering purposes ) ( second revision ).
fSpecification for wrought aluminium and aluminium alloy, bars, rods and sections
( for general engineering purposes ) ( second revision ).
^Specification for anodic coatings on aluminium ( second revision ).
23
IS : 2441 - 1984
5.10.3,4 Mill finish — This finish is suitable for industrial
application.
5.10.4 Erection — The aluminium false ceiling trays may be placed
in the exposed grid frame or clipped in the concealed grid system. The
handing of the main Ts shall be done with sliding hangers and 5 to
6 mm painted mild steel rods or galvanized wires. The grid shall be
truly levelled and the joints of the trays made straight and parallel.
5.11 Expanded Polystyrene
5.11.1 Material
5.11.1.1 Expanded polystyrene — This shall be in accordance with
IS : 4671-1961*.
5.11.1.2 Screws — Screws shall be of brass and shall coDform to
IS : 6760-1972t.
5.11.1.3 Framework — The framework may be wood or metal and
in either case it has only its own load to support, the load of expanded
polystyrene being negligible. Very light sections, therefore, are sufficient.
However, members should be of sufficient depth to ensure that the frame
does not sag under its self weight across the given span and width for
easy gluing/screwing of tiles,
5.11.2 Fixing
5.11.2.1 Ceiling layout — Work shall be started from the centre
outward, pushing the small inevitable erection defects to the fringes of
the ceiling. Ceiling dimensions shall be measured and width and length
of centre lines shall be marked. If a dimension is a full odd multiple
of tile size ( that is 4 500 mm -- 9 x 500 mm ) the starter lile shall be
placed with its centre line falling on the dimensions centre lines. If a
dimension is a full even multiple of the tile size ( that is 4 000 -^^ 8 x 5C0
mm ) the starter tile edge shall be placed along the dimension centre
line.
5.11.2.2 Fixing tile
5.11.2.3 With adhesive — The framework should be clean. The
framework shall be wiped to remove dust and loose particles clinging to
members. Adhesive shall be applied on the annular area of tiles. Wait
till adhesive becomes tacky. Tiles shall be fixed in position pressing
adjacent tiles close together along their joint.
♦Specification for expanded polystyrene for thermal insulation purposes.
fSpecification for slotted countersunk head wood screws.
24
IS : 2441 - 1984
5.11.2.4 IVlth screw> — 35 mn long, No. 6 brass screws at the rate
of 4 per 500 mm X 503 mm tile or 6 psr 1 030 mm X 500 mm slab
shall b3 U5ed for fiKin^. Adjacent slabs should be pressed tightly
together along their joint.
5.11.2.5 To metal frame
5.11.2.6 Slabs/tiles shall be fixed by specially designed cleats/ clips ,
etc, supplied along with the framework.
5*11*2.7 Precaution — Care shall be taken to see that the solvents
used to clean adhesive applicable tools shall not be brought in contact
with expanded polystyrene surfaces.
5.11.3 Finish
5.11.3.1 The white expanded polystyrene ceiling may be painted
to any desired shade with plastic emulsion paints or water bond
distemper. Oil paints may be applied over a protective barrier coat of
shellac. A smooth jointless finish can be obtained, if required by
applying a 3 mm layer of plaster of paris direct on expanded
polystyrene surfaces.
5.12 Mineral Wool Board
5.12.1 Materiali
5.12.1.1 Timber — Timber for making ceiling framework and
beading if any shall be from any of the species given in IS : 5390-1984*.
5.12.1.2 Metal T — shall conform to relevant Indian Standard.
5.12.1.3 JSTails — Nails shall conform to IS ; 723-1972t.
5.12.1.4 Screws — Screws shall conform to IS : 6760-1972t.
5.12.1.5 Mineral wool — This shall conform to IS : 3677-1973§o
5.12.2 Fixing
5.12.2.1 Application 1 — A metal ' T ' bar grid of required size of
either aluminium, mild steel or slotted angles shall be suspended first.
Mineral wool of specified thickness to the size of the facing board may be
cut and spot stuck to fibreglass with suitable adhesive.
5.12.2.2 Application 2 — Framework of wooden battens shall be
suspended as detailed in 5.8.
♦Code of practice for construction of timber ceilings {Jirst revision ).
tSpecification for steel countersunk head wire nails {first revision ).
tSpecification for slotted countersunk head wood screws.
§Specification for unbonded rock and slay wool for thermal insulation.
25
IS : 2441 - 1984
Mineral wool about 12 mm less than the size of the facing board
and spot stick fibreglass to the board with adhesive.
Fix the board with the insulation over it to the battens by means of
screws. If desired and if space permits, mineral wool may be rolled
over the suspended false ceiling. Mineral wool may also be cut slightly
oversize and friction fitted between the angles or battens from above.
In both these cases, the facing board will have to be fixed first.
5.12«2«3 Direct under deck insulation of flat concrete roofs — Wooden
battens shall be fixed to the ceiling.
The fixing of mineral wool with a facing board shall be the same
as in Application 2,
5.12.2.4 Application 3 — Under deck insulation of ceiling, when the
false ceiling is being used as a return airplenum.
Sloted angles of size 30 mm X 30 mm shall be fixed to the ceiling
by means of raw plugs at 750 mm centres.
Draw 14 g tie wires from the slots.
Make a mat of mineral wool backed with scrim cloth with a light
coating of plaster of paris or polythene faced hessian and 24 g X 25 mm
mesh wire netting.
Stretch the mat tightly across the angles, holding it in place by means
of wires. The joints of the wire netting should be butted and tightly
laced down with G.I. wire.
5.12.2.5 Application 4 — Mineral wool insulation in under purlin
lining.
Metal clips shall be fixed on the purlins and metal or wooden frame
of required dimension shall be attached to the cHp.
The fixing of mineral wool and facing board is similar as in
application 1 and application 2.
5« 12.2.6 Application 5 Mineral wool insulation in double sheeted asbestos
foof — Wooden battens as spacers shall be fixed over the existing AG
sheets. Mineral wool of specified thickness shall be unrolled between
these spaces. New layer of asbestos cement sheets shall be attached and
bolted tightly. All openings shall be sealed and made water tight.
26
IS : 2441 - 1984
( Continued from page 2 )
Members Represen ting
Shri S. p. Gupta Hindustan-Pilkington Glass Works Ltd, Calcutta
Shri C. V. Ghalam ( Alternate )
Shbi T. N. Gupta Central Building Research Institute ( CSIR ),
Roorkee
Shri N. K. Sanghari ( Alternate )
Shri G. R. Joshi Concrete Association of India, Bombay
Shri P. Srinivasan ( Alternate )
Shri R. L. Kumar The Institution of Surveyor, New Delhi
Shri P. J. Mehta The Institution of Engineers ( India ), Calcutta
Shri B. Natarajan Kent Ceramic Tiles Co Pvt Ltd, Madras
Shri K. S. Pruthi Forest Research Institute & Colleges, Dehra Dun
Shri H. K. Rakhra Engineer- in-Chief *s Branch, Army Headquarters,
New Delhi
Shri J. Ramamurthy ( Alternate )
Shri K. S. Srinivasan National Buildings Organization, New Delhi
Shri A. K. Lal ( Alternate )
Shri Subrato Ray Balmer Lawire & Co Ltd, Calcutta
Shri K. Suryanarayanan Indian Aluminium Company Ltd, Calcutta
Shri Anjan Sen ( Alternate )
27
INTERNATIONAL SYSTEM OF UNITS ( SI UNITS )
Base Units
QyJAKTITTf
Unit
Symbol
Length
metre
m
Mass
kilogram
kS
Time
second
S
Electric current
ampere
A
Thermodynamic
kelvin
K
temperature
Luminous intensity
candela
cd
Amount of substance
mole
mol
Sapplementary Units
QUANTITY
Unit
Symbol
Plane angle
radian
rad
Solid angle
steradian
sr
Derived Units
QpANTITY
Unit
Symbol
Definition
Force
newton
N
1 N - 1 kg.m/s»
Energy
joule
J
1 J = 1 N.m
Power
watt
W
1 W - 1 J/s
Flux
weber
Wb
1 Wb =- 1 V.s
Flux density
tesla
T
1 T = 1 Wb/m»
Frequency
hertz
Hz
1 Hz - 1 c/s (s-i)
Electric conductance
Siemens
S
1 S - 1 A/V
Electromotive force
volt
V
1 V « 1 W/A
Pressure, stress
pascal
Pa
1 Pa = 1 N/m*
niNDIAN STANDARDS INSTITUTION
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Telephones : 26 60 21, 27 01 3T Telegrams : Manaksanstha
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Hegionat Offices : Tahl>han&
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CALCUTTA 700054
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Branch Off fees :
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\2 63 48
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fnspwction Office ( With Sal* Pomt ) :
Institution of Engineers ( India ) Suiidlng, 1332 Shiveii Nagar. PUNE 410006 6 24 36
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